6-Fluoro-3-hydroxy-2-pyrazinecarboxamide (hereinafter, sometimes referred to as “compound A”.) is useful for treatments such as prevention and therapy of infection due to the influenza virus. Compound A is produced from, for example, 6-fluoro-3-hydroxy-2-pyrazinecarbonitrile (hereinafter, sometimes referred to as “compound B”) (Patent Documents 1 and 2).
Meanwhile, compound B is produced from, for example, 6-bromo-3-hydroxy-2-pyrazinecarboxamide (hereinafter, sometimes referred to as “compound D”), which is obtained by brominating 3-hydroxy-2-pyrazinecarboxamide (hereinafter, sometimes referred to as “compound C”) (Patent Document 3).
In addition, compound C is produced from, for example, aminomalonamide (Patent Document 4).